First of all, excuse me for my bad English but this is not my native language. I will do my best so you can understand my problem.

I have a Yamaha MOXF8 synth that I bought 2,5 years ago. During these years, I was using this synth only in studio and I had never used it at a live concert. Last month, I had to use my MOXF8 at some concerts where I discovered the following problem (in this point, let me inform you that I’ve always been a piano player, so my knowledge about music technology is insufficient):

My synth sends monophonic output although I use factory voices with centered pan (Pan indication: C). Specifically, only the Right output signal is delivered to the channel mixer while the Left output signal doesn’t exist or is extremely low (channel mixer was also center panned).

After some advices of a friend (who has the MOXF8 synth too) I did the following. Unfortunately, I didn’t manage to fix it:

I’m not sure if that was exactly the same problem I had before updating and resetting my MOXF, because the man doing the sound mix at concerts had told me that my Left output signal didn’t exist at all.

4. The same problem was also existing in Initial Mode of voices.

5. After that, I entered the Edit Area of the first voice (Full Concert Grand) and I changed the waveforms of the 8 active elements from stereo to mono (Indication Mn at the end of waveform). After I changed all 8 waveforms to mono, the problem was solved. The Right output signal sent to the channel mixer was exactly the same with the Left output signal. Unfortunately, at this time, I faced a new problem (which may be the same with the old one, I’m not sure). Some keys were sending weaker signal than others. These keys happens to be the same that had problem sending stereo before editing the voice (D3, E3, D4 etc). You can see what I’m saying in the following video:
https://www.dropbox.com/s/l7efb0kgabi4rtf/moxf8_test.mp4

During that test, I noticed that voices made of waveforms that don’t have stereo (St), right (R), left (L) or Mono (Mn) indication at the end have no problem producing Stereo Output (same Left and Right signal).

Of course, I don’t want to change the waveforms of voices from stereo to mono because, as you can understand, the sound quality is too bad.

Also, I would like to inform you that I have tried the above steps with 3 different channel mixers.

And now, these are my questions:

1. First of all, is there anyone that had the same problem? Did he/she manage to fix it?

2. Is there any other test that I could try to see where the problem is?

3. Since it is not a problem of cable outputs or cables or channel mixer (in step 5 I managed to produce stereo sound), is there a possibility to be a hardware problem or keyboard problem? I wonder why specific keys produce weaker signal at step 5.

Since there was nothing more I could do, my friend suggested me to visit this forum asking for any advice.

I have a similar problem kind of… Right channel from Stereo Output deliveres a low signal, distorted..and then it get back to normal.. I don t understand why is happening this, and also, why is working just fine for hours and then suddendly has this problem no matter where i M listening, headphones, powered monitors..